Winding for direct current dynamo armatures having more than two superimposed coil sides per slot



March 31, 1936. H GROB 2,035,47

WINDING FOR DIRECT CURRENT DYNAMO ARMATURES HAVING MORE THAN TWOSUPERIMPOSED COIL SIDES PER SLOT Filed OCT. 9, 1930 AZ V 7 I Q y A/I 7 XD2 M 0 G I O i B Z l f l I A W X L I 6 J E F B l|1 1 I Q A 543 3 fl fi3i2 I? M A TTORNE Y5 Patented Mar. 31, 1936 UNITED STATES PATENT OFFICEHugo Grob, Berlin, Germany, assignor to N. V. Machinerieen-en ApparatenFabrieken Meaf,

Utrecht, Netherlands Application October 9, 1930, Serial No. 487,409 InGermany October 10, 1929 9 Claims.

This invention relates to motor or generator construction, and moreparticularly to the armature construction therefor.

One of the objects of this invention is to provide an armature,particularly for a machine handling direct current, which is simple inconstruction, practical in form, and which may be economically produced.Another object is to provide a direct current armature in which, for agiven size of core, a maximum output rating may be obtained. Anotherobject is to provide an armature of the above mentioned character whichis dependable, thoroughly practical, and eflicient in operation. Anotherobject of this invention is to provide an armature of the abovementioned character which will have improved commutation characteristicsand which, particularly, will achieve a reduction of sparking at thecommutator and a reduction of objectionable heating. Other objects willbe in part obvious or in part pointed out hereinafter.-

The invention accordingly consists in the features of construction,combinations of elements, and arrangements of parts, all as will beillustratively described herein and the scope of the application ofwhich will be indicated in the following claims.

In the accompanying drawing, in which are shown several of the variouspossible embodiments of my invention,

Figure 1 is a fragmentary cross section through a slotted portion of anarmature and includes a diagrammatic representation of the connectionsto the commutator, and

Figure 2 is a view similar to that of Figure 1 but showing a modifiedform of my invention, with a different arrangement of conductors in thearmature slot.

Similar reference characters refer to similar parts throughout theseveral views in the drawing.

As conducive to a clearer understanding of certain features of myinvention, it may at this point be noted that, in the commercialproduction of direct current motors and generators, it has been foundexpedient and desirable to carry a supply of only a minimum number ofdifferent sizes of armature core punchings or laminations. It is thennecessary to use any one type of punching for machines of severaldifferent ratings. With a change of rating, such as a change in voltageof the machine or a change in its rated speed or rated current output,the number of conductors per slot of necessity must difier. One

of the dominant aims of this invention is to provide a simple andthoroughly practical manner of using standard punchings, core sizes, andcoils to produce a machine of simple, practical and inexpensiveconstruction, yet one which is highly efficient in operation and one inwhich 5 commutation troubles are minimized.

As further conducive to a clearer understanding of certain features ofmy invention, the following may be pointed out:-

The commutator segments in the case of D. C. 10 dynamo armatures are,generally speaking, equal in number to the number of wires or coil sidesrespectively situated in the extreme peripheral position. In those casesin which neither brush displacement nor reversing poles may be or are 15to be employed, and in which, therefore, the number of wires in relationto one commutator segment require to be reduced as far as possible, thenumber of segments have to be increased as compared with the usualembodiment, for ex- 20 ample, doubled. In this case, however, it is nolonger possible to arrange all coil sides, as is the rule, in twocircumferential layers. The coil sides, therefore, have to be arrangedin four circumferential layers and in that case, in each slot, 25 fourcoil sides lie above each other.

The provision of, for example, two-by-two winding elements in a radialdirection of the slots necessitates that the number of superimposedwires situated in the one slot be a multiple of 30 the number of thewinding elements. Now it may occur that, from an economical standpoint,the most desirable number of wires in a radial slot layer is, forexample, six, and in such cases it has hitherto been necessary to employeight wires 35 in each radial slot layer, i. e. an unnecessarily highnumber of armature conductors resulting in a considerably increasedresistance of the armature, i. e. in diminished capacity of the dynamo,assuming the number of slots could not be 40 sufficiently reduced.Further the increased radial length of the slots, necessary on accountof the increased number of wires in one radial layer, involves asubstantially less perfect commutation.

The present invention relates to a method of 45 winding and a windingwhich enables a number of wires in a radial layer, which is not comemensurable with or a multiple of four, to also be employed in such casesin which the superimposed wires situated in the radial direction of 50the slot require to be divided into four coil sides. The inventionincludes the feature of not making the number of wires distributed overthe segments the same in the case of all commutator segments, butalternately greater and less than 55 that which would conform with themost economical nominal value.

Referring now to the drawing and more particularly to Figure 1, there isshown at T a section of a portion of an armature core with a slottedportion S in which is laid, for example, the four coil sides C, D, L andK of a portion of the armature winding. The coil sides are maintainedsecure in the slot by the top stick U which interfits with the groovedportions V provided in the upper portions of the slot wall. Each of thebottom coil sides C and D comprises two individual conductors woundparallel. The coil including the lower coil side C may, for example, layoff to the left where it interfits another slot (not shown) in which itbecomes the second coil side from the bottom. The coil including thesecond coil side D may, for example, lay 01f to the right and be lodgedin a third slot (not shown) in which it has its other coil side at thebottom.

The coil sides K and L each comprise, for example as shown, fourconductors connected to form two individual groups of twoseries-connected conductors in each group, lying in the same radiallayer of conductors, both groups being wound parallel.

Conductors C and C of the bottom coil side C are respectively connectedby conductors E and F to the respective commutator segments A and A ofthe commutator A. The conductors K and K of the third coil side K arerespectively connected by conductors M and N to the respectivecommutator segments A and A Conductors D and D of the second coil side Dare respectively connected by the leads G and J to the commutatorsegments B and B of the group B which is suitably spaced along thecommutator periphery from the segments of group A. The top coil side Lhas its parallel conductors L and L respectively connected by means ofconductors O and P to the respectively intervening commutator segments Band B It is to be noted that the parallel-wound conductors of each coilside are connected to comcoil side L are parts of coils laying off tothe right and are connected to the segment B of the commutator. It is tobe further noted that it is the coil sides of the smaller number ofampereturns which are placed in the bottom of the slots.

, With this construction the coils of lesser number of ampere-turns areso positioned that their respective self-inductances are approximatelythe same as the self-inductances of the coils having the larger numberof ampere-turns which are positioned in the upper portions of the slots,

since, for similar coils, the inductances increase with the depth towhich they are placed within the slot. Thus I achieve a compensationbetween the variously sized coils and a consequent improvement incommutation.

The arrows indicated by points (representing arrow heads) and thecrosses, representing arrow tails, indicate not the direction of thecurrent but the direction of the single wires of the winding departingfrom the inner point of connection to the commutator.

In the hand-wound armature construction, in which the various layers ofwindings are shown in Figure 2, the lower layer C is connected byconductors E and F to the commutator segments A and A of the group ofsegments A and is connected in series with a layer of conductorscorresponding with the layer D, but situated in another slot, laying offto the left. The next layer of conductors D is connected by end turns Gand. J to the commutator segments B and B of the group of segments B,being connected in series with the conductors of a layer in another slotlaying off to the right, corresponding with the layer C. The conductorsof the next layer H are connected with the layer W over conductors ofanother slot laying off to the left, corresponding with the layer I. Theconductors of the layer H are spaced from the layer W by the interveninglayer I and are connected by end turns Q and R to the commutatorsegments A and A of group A. The aforementioned layer of conductors I isconnected with the layer X over conductors in another slot laying ofi tothe right, corresponding to the layer W, by means of the end turns Y andZ is taken to the commutator segments B and B of the group of segmentsB. Thus, with this construction, one layer W of the seriesconnectedgroups H and W is sandwiched in between the group of series-connectedconductors I and X. Also one layer I of the group of seriesconnectedconductors IX is sandwiched in between the layers H and W of the groupof seriesconnected conductors HW. This tends to equalize the inductancesof both kinds of coils as will now be clear in View of what has beenabove set forth in connection With the arrangement of Figure 1. Anequalization of the inductances of the coils H-W and IX (which are ofgreater number of ampere-turns) and of coils C and D (which have alesser number of ampereturns) is effected by locating the coils oflesser turns at the base of the slots. also, the arrows indicated bypoints (representing arrow heads) and the crosses (representing arrowtails) do not indicate the direction of the current flow but thedirection of the single wires of the winding departing from the innerpoint of connection to the commutator.

Thus, it will be seen that, due to certain features of my invention,there is provided an armature winding in which, for a number of armatureWires lying above each other in a radial direction and which number isnot commensurate with or is not a multiple of four, the possibilityexists of arranging four coil sides aboveeachother in a radial directionin order to be able to employ an increased number of commutator segmentsfor insuring good commutation. Thereby it is made possible to provide arelatively high number of segments in the commutator without beingforced to increase the number of conductors lying above each other inradial direction in the slots.

Thus it will be further seen that, with my invention, there is providedan armature winding in which, for a given size of armature core and slotconstruction, the slots may be filled with the various conductors togive an efiicient and compact construction and yet by virtue of theequalization and distribution of the armature coil inductance, thecommutation is improved. It will also be seen that there has beenprovided in this invention a construction in'which the several objectshereinbefore noted together withmany thor- In Figure 2, V

-oughly practical advantages are successfully achieved. It will be seenthat the construction is of a thoroughly practical nature, is capable ofsimple and inexpensive manufacture, and is well adapted to meet thevarying conditions of actual use.

As many possible embodiments may be made of the above invention and asmany changes might be made in the embodiment above set forth, it is tobe understood that all matter hereinbefore set forth or shown in theaccompanying drawing is to be interpreted in an illustrative and not ina limiting sense.

I claim:

1. In apparatus of the character described, in combination, a slottedarmature core, a commutator having a plurality of segments, a pluralityof groups of parallel-wound conductors spaced within any one slot ofsaid armature core, and connections from the conductors of alternategroups to adjacent commutator segments.

2. In a direct current machine including a slotted armature and acommutator, an armature winding comprising a plurality of groups ofparallel-wound conductors spaced within the base of said armature slots,and a second plurality of groups of parallel-wound conductors spaced inthe upper portions of said armature slots, and means for connectingparallel-wound conductors of said first mentioned group to alternatecommutator segments, and means for connecting parallel conductors of oneof said second mentioned groups to segments intervening said firstmentioned group.

3. In apparatus of the character described, in combination, an armature,a commutator having a plurality of segments, an armature windingcomprising single coils with different numbers of windings and whichcoils are arranged in such a way that in each slot of the armature fourcoil sides lie above each other in radial direction, and connections forconnecting windings of certain of said coils to alternate commutatorsegments, and means for connecting windings of others of said coils tosegments intervening said alternate commutator segments.

4. In apparatus of the character described, in combination a slottedarmature, a commutator having a plurality of segments, an armaturewinding comprising two groups of coils, the one group consisting ofcoils with a smaller number of conductors than those of the other group,the said coils being arranged in such a way, that in each slot two coilsides with a smaller number of conductors lie on the bottom of the slotand two coil sides with a larger number of conductors lie above thesecoil sides, and connections from said coils to the said commutator.

5. In armature construction, in combination, a slotted armature core, acommutator having a plurality of segments, a winding comprising groupsof coils, one group consisting of coils with a smaller number ofconductors than those of another group, the coils of the said groupsbeing arranged in such a way that in each armature slot there arecontained a plurality of coil sides, at least one of which is of a coilof said one group and at least another of which is of a coil of saidother group, connections from the conductors of the coils of one groupto alternate commutator segments, and connections from the conductors ofthe. coils of another group to intervening oommutator segments.

6. An armature construction as claimed in claim 5 in which the coil sideat the bottom of the slot is of a coil of the group having a smallernumber of conductors.

7. An armature construction as claimed in claim 5, in which there are atleast four coil sides in each armature slot, and in which the coil sidestherein that are nearer the bottom of the slot are of coils having asmaller number of conductors.

8. An armature construction as claimed in claim 5, in which the saidcoil sides in the armature slot are positioned at difierent radialdistances from the axis of the said armature core and in whichdifferences in the numbers of conductors in the coils of said groupsfrom the mean or average value thereof are relatively small and inconjunction with the said different radial distances of the said coilslots, give said coils of different numbers of conductors inductivereactances at least approximating equality.

9. In apparatus of the character described, in combination, a slottedarmature, a commutator having a plurality of segments, an armaturewinding comprising two groups of coils, the one group consisting ofcoils with a smaller number of conductors than those of the other group,the said coils being arranged in such a way, that in each slot two coilsides with a smaller number of conductors lie on the bottom of the slotand two coil sides with a larger number of conductors lie above thesecoil sides and the departures, from the mean or average value, in thesaid numbers of conductors in the coils of said two groups beingrelative- 1y small and proportioned, with respect to the difierences inthe magnetic circuits of said coils of said two groups, so that theinductive reactances of said coils at least approximate equality, andconnections from said coils to the said commutator.

HUGO GROB.

